Answer to your first question: No the save was just after I was on the other side of the water.

Steps:
1) went to folder SE1/cfg
2) opened autoexec.cfg with notepad
3) removed the line ai_norebuildgraph "1"
4) saved the file
5) Started Sin
6) opened the save before I trigger the force field, ie just when I land on the other side of the water
7) Once loaded I see straight away the message AI disabled
8) I try your step next, press ~ that gives me console
9) copy paste ai_norebuildgraph "0" and press submit
10) reload the same save game and no change. Ai disabled.

I can walk up to the door, the force field traps me in but no movement from the characters????